South Africa has released its first verified numerical wind atlas, which will help identify wind energy development sites in three provinces as the country pushes to increase its use of renewable energy sources.
The Wind Atlas for South Africa, launched Deputy Energy Minister Barbara Thompson on Tuesday, brings together 30 years' worth of data verified over a year by 10 measurement masts and data collection systems installed in selected areas of the Eastern, Western and Northern Cape provinces in August 2010.

The data is graphically displayed on the project website, enabling its users to predict key parameters such as wind speed, frequency, direction and estimated power output, and will be updated as measurements continue over the next two years.

Moving towards renewable energy
Speaking at Tuesday's launch, Thompson said the initiative was in line with the government's objective of meeting the needs of a fast growing economy "without compromising our commitment to sustainable development".

Energy from renewable sources will be expected to make up a substantial 42% of all new electricity generation in South Africa over the next 20 years, according to the government's Integrated Resource Plan (IRP), a 20-year projection on electricity supply and demand in the country.

Thompson noted that, based on studies done in the past, South Africa is widely acknowledged to have good wind energy resources along its coast and in some inland areas.

Overcoming the lack of information
There remained, however, a dearth of verifiable quantitative assessments to back up these findings.

"As we embark on our ambitious renewable energy programme, the need for reliable, accurate and representative data on wind becomes critical," Thompson said. "One of the major challenges hampering large scale utilization of wind energy is knowing the practical exploitable wind energy potential in the country."

The wind atlas overcomes this obstacle, Thompson said, providing data that will "help developers in planning and project preparation of bankable projects, siting of turbines as well as siting of wind farms".

At the same time, the project is building local capacity in wind resource assessment through the participation of the South African Weather Service, the University of Cape Town's Climate System Analysis Group, and the Centre for Scientific and Industrial Research, managed by the SA National Energy Development Institute.

According to Engineering News, the Technical University of Denmark's (DTU's) wind energy department is also involved, with funding of R22-million to date provided by South Africa's Department of Energy, the Danish Embassy in SA, and the UN Development Programme's Global Environment Facility.

The DTU's Jens Hansen told Engineering News that a mesoscale climate model with a 5km x 5km resolution had been created, using 30 years' worth of meteorological global reanalysis data, in order to generate the wind atlas.

The atlas had then been verified against the 10 stations set up to measure wind speeds 80 metres above ground level.

Hansen told Engineering News the correlation between the atlas and real measurements was pleasing. "This is world class, there is nowhere in the world that has a better wind atlas than this one."